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A prototype communications antenna embroidered into cloth, held by John Volakis, Director of the ElectroScience Laboratory at Ohio State University. (Al Zanyk/Ohio State University)
That fashionable shirt on the department store clothing rack may one day double as an omnidirectional antenna to boost electronic communication reception.
Research engineers at Ohio State University have reported success in embedding a reliable omnidirectional antenna system directly into clothing fabric, creating a highly functioning wearable system for soldiers, police, firefighters, astronauts—and even the general public, including the elderly and disabled—to potentially use when communicating with others during emergencies and other situations.
The new antenna design uses plastic film and metallic thread sewn into clothing and boasts a range four times greater than the traditional “whip” antenna used by the military. It was reported on in a recent issue of the journal IEEE Antennas and Wireless Propagation Letters.
“Our primary goal is to improve communications reliability and the mobility of the soldiers,” Chi-Chih Chen, a research associate professor of Electrical and Computer Engineering at Ohio State and a co-author of the research paper, said in a university press release. “But the same technology could work for police officers, fire fighters, astronauts—anybody who needs to keep their hands free for important work,” as opposed to carrying a large and unwieldy antenna and related equipment.
“Typically, body-worn antennas suffer from pattern nulling that decreases communication reliability,” Dr. Chen and his colleagues reported in their article, adding how their work introduces ways to get around these problems.
Dr. Chen explains that studies examining how to embed a viable antenna system into clothing is not new. However, he says, his team’s research builds upon such work by combining elements of previous studies in new ways, including introducing a computer control device that enables multiple antennas to work together effectively in a single piece of clothing.
These refinements enable Ohio State’s antenna system to send and receive signals effectively in all directions, even through walls, inside hallways, and deep inside buildings without encountering “dead spots”—unlike antennas used in many cell phones and iPhones—and without a need for the wearer to carry an external antenna.
Postdoctoral researcher Lanlin Zhang embroiders metallic thread onto cloth with a sewing machine as John Volakis, Director of the ElectroScience Laboratory at Ohio State University, looks on. (Al Zanyk/Ohio State University)
In the system, multiple antennas sewn into the clothing surround the body and work in concert to transmit or receive signals, no matter which way a person is facing. The integrated computer control device senses body movement and switches between the antennas to activate the one that will perform best given the body’s position.
Because of its adaptability to various situations, the Ohio State researchers predict it will also be ideal for use by the general public as well. Co-author John Volakis, the Roy & Lois Chope Chair Professor and Director of the ElectroScience Laboratory at Ohio State, for example, envisions the elderly or disabled could wear such clothing to enable them to communicate in case of emergency, without the stigma they might feel in wearing a more visible assistive device.
In their study, the engineers created a prototype antenna by etching thin layers of brass on a light and flexible commercially available plastic film, called FR-4, that was then sewn into a vest at four sites—the chest, back, and both shoulders.
The computer controller—a metal box a little smaller than a credit card and an inch thick—was worn on a belt.
Laboratory tests results showed that the experimental antenna system provided significantly greater signal strength compared to a conventional military “whip” antenna, enabling a range of communications four times larger.
The engineers documented that the new antenna system worked in all directions, even as they tested it inside the hallways of a laboratory location where walls, doors, and windows would normally produce signal interference.
Dr. Chen estimates that the antenna systems, as demonstrated in the prototype, would initially cost $200 per person to implement, but mass production would bring that cost significantly down, he adds. As a result of their work with technology and fabric, he and his colleagues have added a typical home sewing machine to their array laboratory equipment.
Dr. Volakis said, “Imagine a vest or shirt, or even a fancy ball gown made with this technology. The antennas would be inconspicuous, and even attractive. People would want to wear them.”Michael Dabney, a former bioscience communicator at the University of California, San Diego, is a freelance writer specializing in science and education, and an adjunct faculty member in Communications at National University in San Diego, Calif.
